by Jeff Gluck, USA TODAY Sports

by Jeff Gluck, USA TODAY Sports

BROOKLYN, Mich. - NASCAR Sprint Cup Series points leader Jimmie Johnson lost control of his No. 48 car and crashed nose-first into the Turn 4 wall at Michigan International Speedway on Saturday morning, requiring him to use a backup car.

Johnson was uninjured, but will have to start from the rear of the field in Sunday's Pure Michigan 400 after qualifying third on Friday. He ended the final Cup practice Saturday as the fastest driver (195.925 mph), but that was before he crashed the car.

Roughly 20 minutes into the practice, Johnson spun on his own and wrecked. Drivers go into the corners at more than 200 mph at Michigan.

"I'm a little puzzled as to why I spun out going in (to the corner), because I've had great entry stability," Johnson said. "I got a little close to the 27 (Paul Menard), but then again, it's not like I was right on him. To me, it felt like I lost downforce just from the traffic scenario.

"Either way, we have a torn-up car and we will have to work hard to get this one ready to go."

Johnson's backup car, which he used to dominate the Dover race in June before losing on a late restart penalty, made several laps before practice ended.

Juan Pablo Montoya was second-fastest, followed by Greg Biffle, Kurt Busch and Jeff Gordon. Austin Dillon, substituting for the injured Tony Stewart, was the sixth-fastest driver.

Michigan International Speedway is one of only five tracks on the Sprint Cup schedule where Johnson has never won. He's 0-for-23 in Cup races at Michigan.